The text and images in this article were originally published on March 4, 1999, and reflect information about the asteroid trail in Centaurus available at that time.
A Mote in Hubble’s Eye
On April 6, 1994 NASA’s Hubble Space Telescope (HST) was performing a detailed study of the Sun’s nearest stellar neighbor, Proxima Centauri, using the Fine Guidance Sensors to search for small deviations in the position of Proxima Centauri that could reveal the presence of an unseen planetary companion. Rather than sit idle while this study went on, the Wide Field and Planetary Camera 2 (WFPC2) was activated using the observing strategy set out in a program initiated by Dr. Ed Groth (Princeton) designed to make use of this otherwise wasted time. The image captured by this WFPC2 parallel observation is a typical Milky Way star field in the constellation Centaurus. Such images can be used to study the evolution of stars that make up our galaxy. Most of the stars in this image lie near the center of our galaxy some 25,000 light-years distant. But one object, the blue curved streak, is something much closer. An uncatalogued, mile-wide bit of rocky debris orbiting the Sun only light-minutes away strayed into WFPC2’s field while the image was being exposed. This and about a hundred other interlopers have been found by Jet Propulsion Laboratory astronomers Dr. Robin Evans, Dr. Karl Stapelfeldt, and collaborators, who have systematically searched the HST archive for these nearby objects. Their analysis indicates this asteroid’s orbit could cross Mars’ path. Seen briefly by HST, these asteroids are too small and faint to track from the ground long enough for precise orbits to be determined. They are destined to return to their unseen wanderings for hundreds or thousands of years until once again, by chance, they may flicker across the view of some watchful eye peering off into the depths of space.
Featured Image Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)
Acknowledgment: R. Evans and K. Stapelfeldt (Jet Propulsion Lab)
Fast Facts about the Asteroid Trail in Centaurus
About this Object
|Object Name:||Asteroid Trail in Centaurus|
|Position (J2000):||R.A. 14h 28m 08.74m |
Dec. –62° 45′ 43.20″
|Dimensions:||The image is 2.7 arcminutes on the vertical side.|
About the Data
|Exposure Date:||April 6, 1994|
|Exposure Time:||33 minutes|
|Filters:||Red: F814W(I); Green: F814W + F606W; Blue: F606W(Wide V)|
|Principal Astronomers:||E. J. Groth (Princeton) and collaborators|
About the Asteroid
|Asteroid Trail Length:||19 arcseconds|
|Asteroid Diameter:||1.25 miles (2 kilometers)|
|Asteroid Distances:||The asteroid is 87 million miles (0.93 A.U.) from Earth. It is 156 million miles (1.68 A.U.) from the Sun.|
|Principal Astronomers:||R. Evans, K. Stapelfeldt (Jet Propulsion Lab) and collaborators.|
About this Image
|Image Credit:||NASA, ESA, and the Hubble Heritage Team (STScI/AURA)|
|Release Date:||March 4, 1999|
|Orientation/Scale:||North is 70° CCW from up. East is to the left of North.|
Additional Info on Proxima Centauri
The yellow “chevron” shapes in the image above are the fields of view imaged by the WFPC2 detector. Overlaid on a Digitized Sky Survey image, they help highlight the relative positions the asteroid trail and Proxima Centauri.
The asteroid trail in Centaurus was a serendipitous discovery made using the Wide Field and Planetary Camera (WFPC2) while NASA’s Hubble Space Telescope (HST) was performing a detailed study of the Sun’s nearest stellar neighbor, Proxima Centauri, using the Fine Guidance Sensors. This primary program by Dr. Benedict, Dr. Jefferys (both of the University of Texas) and collaborators was designed to search for small deviations in the position of Proxima Centauri that could reveal the presence of an unseen planetary companion.
Proxima Centauri is close enough to our solar system that its motion (proper motion as opposed to parallax) can be measured as it moves against the background of more distant stars.
This movie was also constructed from the Digitized Sky Survey (DSS) images of this star. (The DSS is also available via SkyView.) The image colored blue in the movie was taken through a blue filter in 1976 while the one colored green was taken through a green filter 6 years later.
The Digitized Sky Survey (DSS) was the work of Barry Lasker and his group at Space Telescope Science Institute.